“读取-求值-输出”循环（英语：Read-Eval-Print Loop，简称REPL）是一个简单的，交互式的编程环境。这个词常常用于指代一个Lisp的交互式开发环境，但也能指代命令行的模式和例如APL、BASIC、Clojure、F#、Haskell、J、Julia、Perl、PHP、Prolog、Python、R、Ruby、Scala、Smalltalk、Standard ML、Swift、Tcl、Javascript这样的编程语言所拥有的类似的编程环境。这也被称做交互式顶层构件（interactive toplevel）。

A read–eval–print loop (REPL), also known as an interactive toplevel or language shell, is a simple, interactive computer programming environment that takes single user inputs (i.e. single expressions), evaluates them, and returns the result to the user; a program written in a REPL environment is executed piecewise. The term is most usually used to refer to programming interfaces similar to the classic Lisp machine interactive environment. Common examples include command line shells and similar environments for programming languages, and is particularly characteristic of scripting languages.